// Animancer // https://kybernetik.com.au/animancer // Copyright 2018-2024 Kybernetik //

#pragma warning disable CS0649 // Field is never assigned to, and will always have its default value.

using Animancer.Units;
using System;
using UnityEngine;

namespace Animancer.Samples.AnimatorControllers.GameKit
{
    /// <summary>
    /// A <see cref="CharacterState"/> which keeps the character standing still and occasionally plays alternate
    /// animations if it remains active for long enough.
    /// </summary>
    /// 
    /// <remarks>
    /// <strong>Sample:</strong>
    /// <see href="https://kybernetik.com.au/animancer/docs/samples/animator-controllers/3d-game-kit/idle">
    /// 3D Game Kit/Idle</see>
    /// </remarks>
    /// 
    /// https://kybernetik.com.au/animancer/api/Animancer.Samples.AnimatorControllers.GameKit/IdleState
    /// 
    [AddComponentMenu(Strings.SamplesMenuPrefix + "Game Kit - Idle State")]
    [AnimancerHelpUrl(typeof(IdleState))]
    public class IdleState : CharacterState
    {
        /************************************************************************************************************************/

        [SerializeField] private ClipTransition _MainAnimation;
        [SerializeField, Seconds] private float _FirstRandomizeDelay = 5;
        [SerializeField, Seconds] private float _MinRandomizeInterval = 0;
        [SerializeField, Seconds] private float _MaxRandomizeInterval = 20;
        [SerializeField] private ClipTransition[] _RandomAnimations;

        private float _RandomizeTime;

        // _RandomizeDelay was originally handled by the PlayerController (Idle Timeout).
        // The min and max interval were handled by the RandomStateSMB on the Idle state in IdleSM.

        /************************************************************************************************************************/

        protected virtual void Awake()
        {
            Action onEnd = PlayMainAnimation;
            for (int i = 0; i < _RandomAnimations.Length; i++)
            {
                _RandomAnimations[i].Events.OnEnd = onEnd;

                // We could just do `...OnEnd = PlayMainAnimation` instead of declaring the delegate first, but that
                // assignment is actually shorthand for `new Action(PlayMainAnimation)` which would create a new
                // delegate object for each animation. This way all animations just share the same object.
            }
        }

        /************************************************************************************************************************/

        public override bool CanEnterState => Character.Movement.IsGrounded;

        /************************************************************************************************************************/

        protected virtual void OnEnable()
        {
            PlayMainAnimation();
            _RandomizeTime += _FirstRandomizeDelay;
        }

        private void PlayMainAnimation()
        {
            _RandomizeTime = UnityEngine.Random.Range(_MinRandomizeInterval, _MaxRandomizeInterval);
            Character.Animancer.Play(_MainAnimation);
        }

        /************************************************************************************************************************/

        protected virtual void FixedUpdate()
        {
            if (Character.CheckMotionState())
                return;

            Character.Movement.UpdateSpeedControl();

            // We use time where Mecanim used normalized time because choosing a number of seconds is much simpler than
            // finding out how long the animation is and working with multiples of that value.
            AnimancerState state = Character.Animancer.States.Current;
            if (state == _MainAnimation.State &&
                state.Time >= _RandomizeTime)
            {
                PlayRandomAnimation();
            }
        }

        /************************************************************************************************************************/

        private void PlayRandomAnimation()
        {
            int index = UnityEngine.Random.Range(0, _RandomAnimations.Length);
            ClipTransition animation = _RandomAnimations[index];
            AnimancerState state = Character.Animancer.Play(animation);
            state.FadeGroup.SetEasing(Easing.Sine.InOut);
        }

        /************************************************************************************************************************/
    }
}